<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>HTML5 GetUserMedia Demo</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
</head>
<body>
    <input type="button" title="开启摄像头" value="开启摄像头" onclick="getMedia();" /><br />
    <video height="120px" autoplay="autoplay"></video><hr />
    <input type="button" title="拍照" value="拍照" onclick="getPhoto();" /><br />
    <canvas id="canvas1" height="120px" ></canvas><hr />
    <input type="button" title="视频" value="视频" onclick="getVedio();" /><br />
    <canvas id="canvas2" height="120px"></canvas>

    <script type="text/javascript">
        var video = document.querySelector('video');
        var audio, audioType;

        var canvas1 = document.getElementById('canvas1');
        var context1 = canvas1.getContext('2d');

        var canvas2 = document.getElementById('canvas2');
        var context2 = canvas2.getContext('2d');

        navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;
		window.URL = window.URL || window.webkitURL || window.mozURL || window.msURL;

        var exArray = []; //存储设备源ID
		/*
        MediaStreamTrack.getSources(function (sourceInfos) {
            for (var i = 0; i != sourceInfos.length; ++i) {
                var sourceInfo = sourceInfos[i];
                //这里会遍历audio,video，所以要加以区分
                if (sourceInfo.kind === 'video') {
                    exArray.push(sourceInfo.id);
                }
            }
        });
        */
		
		function enumerateDevicesCallback( sourceInfos){
					 for (var i = 0; i != sourceInfos.length; ++i) {
						var sourceInfo = sourceInfos[i];
						//这里会遍历audio,video，所以要加以区分
						if (sourceInfo.kind === 'video') {
							exArray.push(sourceInfo.id);
						}
					}
				} 
			   
				if(MediaStreamTrack.getSources){
				  MediaStreamTrack.getSources(enumerateDevicesCallback);
				} else{
				  navigator.mediaDevices.enumerateDevices().then(enumerateDevicesCallback);
				}
		
		
		
        function getMedia() {
            if (navigator.getUserMedia) {
                navigator.getUserMedia({
                    'video': {
                        'optional': [{
                            'sourceId': exArray[1] //0为前置摄像头，1为后置
                        }]
                    },
                    'audio':true
                }, successFunc, errorFunc);    //success是获取成功的回调函数
            }
            else {
                alert('Native device media streaming (getUserMedia) not supported in this browser.');
            }
        }

        function successFunc(stream) {
            //alert('Succeed to get media!');
            if (video.mozSrcObject !== undefined) {
                //Firefox中，video.mozSrcObject最初为null，而不是未定义的，我们可以靠这个来检测Firefox的支持
                video.mozSrcObject = stream;
            }
            else {
                //video.src = window.URL && window.URL.createObjectURL(stream) || stream;
				
				try {
                  video.srcObject = stream;} catch (error) {
                  video.src = window.URL.createObjectURL(stream);}
				
				
            }

            //video.play();

            // 音频
            audio = new Audio();
            audioType = getAudioType(audio);
            if (audioType) {
                audio.src = 'polaroid.' + audioType;
                audio.play();
            }
        }
        function errorFunc(e) {
            alert('Error！'+e);
        }

        
        // 将视频帧绘制到Canvas对象上,Canvas每60ms切换帧，形成肉眼视频效果
        function drawVideoAtCanvas(video,context) {
            window.setInterval(function () {
                context.drawImage(video, 0, 0,90,120);
            }, 60);
        }

        //获取音频格式
        function getAudioType(element) {
            if (element.canPlayType) {
                if (element.canPlayType('audio/mp4; codecs="mp4a.40.5"') !== '') {
                    return ('aac');
                } else if (element.canPlayType('audio/ogg; codecs="vorbis"') !== '') {
                    return ("ogg");
                }
            }
            return false;
        }

        // vedio播放时触发，绘制vedio帧图像到canvas
//        video.addEventListener('play', function () {
//            drawVideoAtCanvas(video, context2);
//        }, false);

        //拍照
        function getPhoto() {
            context1.drawImage(video, 0, 0,90,120); //将video对象内指定的区域捕捉绘制到画布上指定的区域，实现拍照。
        }

        //视频
        function getVedio() {
            drawVideoAtCanvas(video, context2);
        }

    </script>
</body>
</html>
